Specimens, samples, and various medicines are sometimes maintained in sealed or sterile containers useful for transporting or storing the contents of the container. Such containers often have a removable cap that may be threaded or press fitted onto or into the container. Such containers are considered “open systems” because the container is initially provided to the technician in a closed state after sterilization. To fill the container, the technician, or filling equipment must first unscrew or otherwise remove the cap, align a dispensing needle or nozzle with the opening, dispense the contents into the container, and replace the cap. Throughout this process, the open configuration of the container presents the potential for contaminants to mix with the contents until the cap is replace and the container is resealed. Withdrawing the contents from a capped container also requires removing the cap and opening the container to the environment that again may not be sterile. Withdrawing the sample may then provide further opportunity for contaminants to mix with the contents.
It is often advantageous to expose the container to extreme cold to preserve the contents inside. However, when submerged in liquid nitrogen for cryopreservation, there is a risk with capped containers that the seal between the cap and the walls of the container may not be maintained and that some liquid nitrogen may leak into the container. Not only does this potentially contaminate the sample, but when the container is warmed to thaw the contents, the rapid expansion of the liquid nitrogen to a gaseous state may cause the container to rupture or explode. Such systems therefore may not be safely immersed into liquid nitrogen and therefore may not be useful for cryogenic preservation.